The most common fire fighting vehicles in use today deliver water to extinguish fires. (Fire trucks, fire boats etc.) Some back-pack or fixed carbon dioxide or chemical systems are used for small fires. When using water for large fires, large quantities are needed. Although water is a useful fire fighting agent for Class 1 (paper and wood) fires, it is slow, and produces much damage to interior structures and equipment etc. In winter freezing of water on hoses and ladders causes problems. Also people must first be removed from burning structures before water can be safely used. Generally, one water hose team of 4 men can extinguish 1200 square feet. For Class 2 fires (oil, gasoline etc.), water is not very effective. Halogen based chemicals such as that available under the brand name Halon, are toxic and also damage equipment. Very large areas, such as entire floors as in the World Trade Center fire, cannot be extinguished using water. For tall buildings, skyscrapers etc the water system depends on internal piping systems which may not always be operational. This invention provides an external, large capacity independent non-toxic, non-damaging fast extinguishing system, which is superior to conventional systems currently used.
In this invention, liquid, cryogenic inert gases are transported to the fire which when converted to gaseous form expand over 700 times at 70° F., and another 4 times at the fire temperature of about 1500° F. A truck carrying 10,000 gallons of liquid will convert to 28 million gallons of gas, which can treat 1800 average size rooms.
Previous patents have disclosed the composition of gases used to extinguish fires, where the oxygen content is reduced (U.S. Pat. Nos. 3,893,514, 4,807,706), and or chemicals are added which impart to the atmosphere heat capacity sufficient to suppress the combustion in the enclosed area (U.S. Pat. Nos. 3,715,438, 3,840,667, 1,926,396). In U.S. Pat. No. 4,807,706, oxygen is reduced and carbon dioxide added into the fire zone, making the atmosphere in the fire zone breathable.
Generally these are fixed in place systems, with means to detect fires and introduce the appropriate gas or chemical, with the agents at room temperature.
This invention comprises liquefying appropriate gases and transporting them to the fire, where the gases are applied directly to the fire in either liquid or gaseous form. This provides an independent external, non-toxic system of fire extinguishing gases which reduce the oxygen content of the enclosed air in the fire zone and /or cools the fuel. The gases permeate into all space quickly, including closed desk drawers, to quickly put out fires.